Zercepac is a biosimilar medication primarily used in the treatment of certain types of cancer, including breast cancer and stomach cancer. As a biosimilar, it is highly similar to the reference product, Herceptin (trastuzumab), and has been shown to have no clinically meaningful differences in terms of safety, purity, and potency. Zercepac works by targeting and inhibiting the function of the HER2 protein, which is overexpressed in some cancer cells and promotes their growth. By blocking the action of this protein, Zercepac helps to slow down or stop the growth of cancer cells. It is administered through intravenous infusion and is often used in combination with other cancer treatments as part of a comprehensive treatment plan.